Torsion bar chair control

ABSTRACT

1,161,464. Seats. STEWART-WARNER CORP. 29 Dec., 1967 [30 Dec., 1966], No. 59130/67. Headings A4J and A4U. In a tilting chair, a back-rest rotates about the axis of a torsion bar 38, which opposes its rearward pivoting motion, while a seat participates in this motion to a reduced extent, by turning about its front pivotal connections 90, by which it is mounted on a stationary support body 22. The ends of bar 38 are secured in extensions 32, 34 of the support body, which has integral side walls 24, 26. The backrest, which is adjustably clamped in angularly adjustable shoe 64, turns plates 44 about bearings 42, carried on bar 38 and applies a moment to the bar 38, by means of screw 50 engaging arm 48, fast with the bar. The rotation of plates 44 is transmitted to the rear of the seat by toggle linkage 56 connected to seat fastenings 84. In another form, pivots 90 are replaced by a torsion bar (100, Figs. 8 and 9, not shown).

Sept; 24, 1968 P. J. WILLIAMS 3,

TORSION BAR CHAIR- CONTROL Filed Dec. 30, 1966 2 Sheets-Sheet l k All"!!! INVENTOIR m; xx mm 64 7 By W PIC-3.6. v 7 7 Attorney P 1968 P. J. WILLIAMS 3,402,964

TORSION BAH CHAIR CONTROL Filed Dec. 30. 1966 2 Sheets-Sheet 2 INVENTOR Pimp J 2/4/24:

Attornev United States Patent 3,402,964 TORSION BAR CHAIR CONTROL Philip J. Williams, Bridgeport, Conn., assignor to Stewart- Warner Corporation, Chicago, 11]., a corporation of Virginia Filed Dec. 30, 1966, Ser. No. 606,222 8 Claims. (Cl. 297-304) ABSTRACT OF THE DISCLOSURE The disclosure of this application relates to a torsion bar chair control having pivotable seat and back supports with the seat and back supports interconnected by a pivotable toggle link at the rear of the seat. The front end of the seat is pivotally connected to a stationary support body carrying the torsion bar on which the back support is rotatably mounted.

This invention relates in general to torsion bar chair controls of the type wherein both the seat and back tilt independently and more particularly to an improved chair control in which the back pivots about a torsion bar and is interconnected with an independently pivotable seat to pivot the seat through a different angle.

In a so-called executive type posture chair, both the seat and back tilt or pivot relative one another to provide greater comfort to the occupant on leaning back. A chair of this type utilizing a torsion bar is disclosed in US. Patent No. 3,240,528. In that patent the torsion bar was engaged at opposite ends by the seat and pedestal for relative tilting movement between the seat and pedestal. The back support was rotatably carried by the torsion bar and a cross bar located at the rear of the seat for tilting the seat when the occupant leaned against the back. This arrangement does not provide the advantages of a torsion bar which is twisted from a center position as, for example, shown in US. Patent No. 3,250,567, while considerable parts and linkages are necessary.

It is therefore one object of the present invention to utilize the advantages of a torsion bar chair control with a simplified linkage for pivoting the back and seat relative to each other and the chair pedestal.

It is another object of the present invention to utilize a center held torsion bar in which the back and seat are pivotable relative to each other and the chair pedestal.

It is another object of the present invention to provide a torsion bar chair control utilizing separate torsion bars for enabling both the back and seat to pivot through different angles relative to the pedestal.

Other objects of the present invention will become apparent on examination of the following specification and claims together with the drawings, wherein:

FIG. 1 is a side elevational view of a chair incorporating .the principles of the present invention;

FIG. 2 is a perspective view partially broken of one chair control used on the chair shown in FIG. 1;

FIG. 3 is a sectional view of the torsion bar lever assembly;

FIG. 4 is a fragmentary sectional view illustrating the bearings encircling the torsion bar;

FIG. 5 is a fragmentary sectional view of the pivot link to the front of the seat support;

FIG. 6 is a sectional view of the toggle link assembly;

FIG. 7 is a sectional view taken through the line 7-7 in FIG. 6;

FIG. 8 is a top elevational view of another chair control utilizing a seat torsion bar;

FIG. 9 is a section view taken along the line 9-9 in FIG. 8; and

FIG. 10 is a fragmentary sectional view taken along the line 1010 in FIG. 8.

3,402,964 Patented Sept. 24, 1968 ice Referring to the drawings, a chair is indicated generally in FIG. 1 by the reference character 10. The chair 10 comprises a chair seat 12 and a chair back 14 both supported on a chair control assembly 16. The chair control assembly 16 in turn is supported on a chair post 18 rotatably carried by a pedestal assembly 20.

The control assembly 16, as best seen in FIG. 2, comprises a support body 22 defined by a pair of spaced side walls 24 and 26 interconnected by a bottom wall 28 and a front wall 29 spaced some distance behind the actual front end of walls 24 and 26. The bottom wall 28 has an aperture in which a post receiving member 30 is staked for receiving the post 18. The member 30 and the post 18 are provided with complementary tapers and key and keyway to ensure a locking fit without the use of special assembly tools. This facilitates separate shipment of the post and support body, as explained in US. Patent 3,285,- 639.

The side walls 24 and 26 each have a U-shaped support bracket 32 and 34 preferably integrally formed thereon and projecting horizontally therefrom adjacent the rear end of the respective side wall with a back leg 36 for each bracket spaced outwardly from the side walls 24 and 26 of the support body. The back leg 36 of each bracket is provided with a rectangular or circular aperture for nonrotatably receiving the end of a correspondingly shaped torsion bar 38.

The torsion bar 38 extends through aligned bearings 40, which are rotatably engaged in side walls 24 and 26 as seen in FIG. 4. The torsion bar also passes through bearings 42 rotatably engaged in a respective one of a pair of spaced hinge plates 44 located intermediate side walls 24 and 26.

The hinge plates 44 form part of a back support assembly 46 which is rotatably mounted by bearings 42 on the torsion bar 38 as, for example, explained in Patent 3,136,- 580 granted June 9, 1964. As explained in that patent a torque bar 48 nonrotatably carried by the torsion bar 38 intermediate the plates 44 is used to adjust the tensioning of the bar by means of a threaded member 50. Threaded member 50 passes through a threaded spacer plate 52 fixed adjacent the front end of plates 44 and serves to apply a torque to the bar in response to a backward leaning movement by the chair occupant.

The opposite or back end of the plates 44 carry a hinge assembly 54 and a toggle assembly 56. The hinge assembly 54 comprises a pin 58 which extends through an a-rcuate slot 60 in each plate 44. The pin 58 also extends through a slot 62 in each side leg 64 of a U-shaped back bracket 66 with the side legs 64 in overlapping engage-- ment with plates 44. A locking lever 68 on one end of pin 58 enables the back bracket to be conventionally locked at a desired angular position with respect to plates 44. A slot 70 in the rear leg of back bracket 66 permits the height of the back 14, which is carried on a bar 72 to be adjusted as desired, and clamped to bracket 66 by means of a hand wheel 74.

The hinge assembly 54 comprises a pair of spaced toggle elements or links 76 joined by an integrally formed transverse bar 78 and pivotally supported on a pin 80 at the lower end of the toggle elements 76. Pin 80 extends through plates 44 and legs 64. The bracket 66 of course swivels or pivots about pin 80 when the angular position of bracket 66 is adjusted relative plates 44. A second pin 82 is pivotally supported in the upper end of the toggle elements 76 and it carries a pair of L-shaped brackets 84 having horizontal legs to which the rear end of seat 12 is fixed. Pins 80 and 82 are supported in respective openings of the toggle by moulder nylon bushings 87 to provide an exceptionally quiet sturdy pivot.

Another pair of L-shaped brackets 88 similar to brackets 84 are pivotally supported on pins 90 passing through respective bushings similar to 87 adjacent the front end of the side walls 24 and 26 of the support body 22. The front end of the seat 12 is fixed to the horizontal legs of brackets 88. The seat 12 is therefore carried on two pairs of pivotable brackets 86 and 88 with brackets 88 being free to pivot about the axis of pins 90 and the brackets 86 being free to pivot on toggle 76 about the axis of pin 82 while the toggle pivots about the axis of pin 80. A stop 91 may be provided on the toggle to prevent excessive forward pivoting thereof. The plates 44 and back in turn pivot about the axis of torsion bar 38.

The distance between torsion bar 38 and pin 80 is somewhat less than half the distance between pin 90 and the connection between the seat and bracket 84. The maximum angle through which the hinge plates 44 pivot about the torsion bar axis is chosen at somewhat less than 18. This limit is set by a stop 92 carried by plates 44 and a rubber bumper or cushion 94 carried by the support body as seen in FIG. 2. The chair occupant on leaning backwards causes the hinge plates 44 to pivot downwards or clockwise as seen in FIG. 2 of the drawings, while at the same time a resisting force is applied to the seat 12 by the occupants legs. Since the distance between the horizontal legs of brackets 84 and 88 is fixed by the seat, and since the pivot axis at pin 90 remains stationary, the bracket 88 and the seat .pivot through a maximum angle dependent on the distance of pin 99 from bracket 84 and pin 80 from bar 38. Since the relationship of these distances is somewhat less than 2 to 1, the bracket 88 and the seat pivot through somewhat less than /2 the angle of the back or a maximum of less than 9. The pressure on the occupants legs is therefore substantially minimized to provide a more comfortable backward leaning position.

The apparatus shown in FIGS. 8, 9 and 10 is basically similar to the apparatus shown in FIGS. 1-7, and similar parts are identified by similar reference characters. Thus a support body 22 carries a post support member for mounting the body 22 on a postsupported by a pedestal. The end walls 36 of the support body are nonrotatably fixed to the ends of the torsion bar 38 and the bar in turn rotatably carries a pair of hinge plates 44. A torque bar 48 is fixed to the bar 38 intermediate plates 44 and a member 50 threaded through plate 52 serves to tension the bar 38. The end walls 36 are provided with a depending lip 95 and a cross web 96 as seen in FIGS. 8 and 10 between the walls of brackets 32 and 34 for increased strength rigidity.

The plates 44 carry a hinge assembly 54 and :a toggle assembly 56 including toggle element 76, pins 80 and 82 and brackets 84 as previously described, but of larger dimension and somewhat different shape than the brackets seen in FIG. 2. Instead of using pivot pins 90 for rotatably mounting L-shaped brackets 88 at the front end of support body 22, a torsion bar assembly 98 is employed.

The torsion bar assembly 98 comprises a torsion bar 100 rotatably supported in side walls 24 and 26 by means of bushings 102. The ends of the bar 100 are nonrotatably fixed in respective L-shaped brackets 104 with the horizontal arms of the brackets 104 being fixed to the seat in a manner similar to brackets 88. Locking elements 106 are provided on the projecting ends of torsion bar 100'.

A torque bar 108 is nonrotatably fixed to the torsion bar 100 intermediate side walls 24 and 25 of support body 22. It will be noted that in the embodiment shown in FIGS. 8 and 9 that the upper portions of the side walls 24 and 26 extend beyond the front wall 29 and that the front wall 29 terminates in a bottom wall 110 for the projecting portions of walls 24 and 26. The bottom wall 110 curves upwardly between the projecting ends of walls 24 and 26 to form a second front wall 112 between the projecting ends of walls 24 and 26. The torque bar 108 is actually an integrally formed wall extending between walls 112 and 29 and interconnected with bottom wall 110 to form a strong rigid support.

As seen by the broken lines in FIG. 9, the action of the apparatus shown in FIGS. 8 and 9 is much the same as that of the apparatus shown in FIGS. 1-7, with the exception being the resilient action secured by torsion bar 100. In response to a backward leaning movement by the chair occupant through a maximum angle of C indicated between broken lines A and B, the hinge pin and plates 44 rotate clockwise as seen in FIGS. 2 and 9. The maximum angle is of course determined by the 10- cations of stop 92 and bumper 94.

The front brackets 104 rotate clockwise about the axis of bar in response to rotation of pin 80. Since the distance between brackets 84 and 104 is fixed by the seat and the pivot axis at bar 100 is fixed, the brackets 104 move through an angle of slightly less than /2C indicated at 0/2 between broken lines D and E. The toggle 76 pivots about pin 80 and bracket 84 does the same about pin 82 under constraint of the seat to maintain the seat aligned as it moves from along broken line F to line F1 tangent to the axis of rotation of brackets 84 and 104. The toggle pivots about axis of pin 80 to permit the seat movement. The seat therefore only rotates through an angle of slightly less than C/ 2 dependent of course on the relative distance between bar 100 and bracket 84 and between bar 38 and pin 80.

The foregoing constitutes a description of an improved chair control whose inventive concepts are believed set forth in the accompanying claims.

What is claimed is:

1. For use in supporting a seat on .a chair having a chair control of the type including a support body carried on a pedestal with a torsion bar nonrotatably secured to said support body in a plane intermediate the ends of said seat for rotatably carrying a back support and interconnected with said torsion bar intermediate the ends of said bar for twisting said torsion bar in response to a backward leaning movement by the occupant of the chair seat to rotate said back support about the axis of said bar, the improvement comprising a toggle rotatably carried by said back support for rotation about a pivot axis spaced a predetermined distance from said bar axis, means fixed to said seat at one position adjacent one end of said seat and rotatably carried by said toggle, other means fixed to said seat at a second position adjacent the Opposite end of said seat, and means for rotatably carrying said other means on said support body for rotation about an axis spaced from said one position by a distance in excess of said predetermined distance for enabling said seat to rotate through a smaller angle than said back support in response to rotation of said back support by said occupant.

2. The apparatus claimed in claim 1 in which said means for rotatably carrying said other means comprises a torsion bar whose ends are nonrotatably secured to said other means and which is interconnected with said support body intermediate the ends thereof.

3. For use with a chair control of the type including a torsion bar interconnected with a support body and a back support for yieldably resisting a backward leaning movement against said back support by the occupant of a chair seat carried by said chair control, the improvement comprising a toggle rotatably carried by said back support at one predetermined distance from the axis of said bar for solely rotational movement on said back support, means fixed to said seat at one position and rotatably carried by said toggle for solely rotational movement on said toggle, and other means fixed to said seat and rotatably carried by said support body at a position spaced from said one position by a distance greater than said predetermined distance for thereby enabling said seat to rotate with said back support through only a predetermined portion of the angle through which said back support is rotated by said occupant.

4. For use with a chair control of the type including a torsion bar interconnected with a support body and a back support for yieldably resisting a backward leaning movement against said back support by the occupant of a chair seat carried by said chair control, the improvement comprising a toggle rotatably carried by said black support at one predetermined distance from the axis of said bar, means fixed to said seat at one position and rotatably carried by said toggle, other means fixed to said seat, and a torsion bar interconnecting said other means and said support body for rotatably carrying said other means on said support body at a position spaced from said one position by a distance greater than said predetermined distance to thereby enable said seat to rotate with said back support through only a predetermined portion of the angle through which said back support is rotated by said occupant.

5. For use with a chair control of the type including a torsion bar interconnected with a support body and a back support for yieldably resisting a backward leaning movement against said back support by the occupant of a chair seat carried by said chair control, the improvement comprising a toggle rotatably carried by said back support at one predetermined distance from the axis of said bar, means fixed to said seat at one position and rotatably carried by said toggle, other means fixed to said seat and rotatably carried by said support body at a p sition spaced from said one position by a distance greater than said predetermined distance for thereby enabling said seat to rotate with said back support through only a predetermined portion of the angle through which said back support is rotated by said occupant, and a stop on said toggle for engaging said back support in order to limit forward pivoting of said seat relative said back support.

6. A combination for use in a chair comprising a chair seat, a support body, a torsion bar nonrotatably secured to said support body adjacent the ends of said bar, aback support, means for rotatably carrying said back support on said bar intermediate the ends of said bar, means interconnecting said back support to said bar intermediate the ends of said bar for twisting said torsion bar in response to a backward leaning movement by the occupant of said chair to rotate said back support about the axis of said bar, a toggle element rotatably carried by said back support at a predetermined distance along a radial line extending in one direction from said axis, means fixed to said seat at one position and rotatably carried by said toggle element, and means fixed to said seat at a second position and rotatably carried by said support body for pivoting movement about an axis located approximately twice said predetermined distance from said one position for enabling said seat to rotate with said back support through an angle approximately one-half the angle through which said back support is rotated.

7. A combination for use in a chair comprising a support body, a torsion bar located in a plane intermediate the ends of the chair seat with the ends of said bar nonrotatably secured to said support body, mean rotatably supporting said torsion bar on said support body intermediate the ends of said torsion bar, a back support, means rotatably carrying said back support on said torsion bar, means interconnecting said torsion bar intermediate the ends of said bar with said back support for twisting said torsion bar in response to a backward leaning move ment by the occupant of the chair seat to rotate said back support about the axis of said bar, a toggle element rotatably carried by said back support for rotation about a pivot axis spaced a predetermined distance from said plane, means fixed to said seat at one position adjacent one end of said seat and rotatably carried by said toggle element, and other means fixed to said seat adjacent the opposite end of said seat, a second torsion bar nonrotatably secured to said other means, and means interconnecting said second bar with said support body for enabling rotation of said other means about the axis of said second bar and spaced from said one position by a distance in excess of said predetermined distance for enabling said seat to rotate through a smaller angle than said back support in response to rotation of said back support by said occupant.

8. The combination claimed in claim 7 in which said means interconnecting said second bar with said support body comprises a wall integrally formed on said support body for nonrotatably engaging said second bar and forming a strong support therefor.

References Cited UNITED STATES PATENTS 2,110,874 3/1938 Herold 297305 2,286,468 6/1942 Cramer et al. 297304 2,329,327 9/1943 Boerner 297304 XR 2,447,601 8/1948 Sengpiel 297305 XR 3,136,580 6/ 1964 Parrott 297304 3,224,807 12/1965 Welch et a1. 297304 3,250,567 5/1966 Parrott 297304 3,240,528 3/1966 Ciuffini et al. 297303 BOBBY R. GAY, Primary Examiner.

G. O. FINCH, Assistant Examiner. 

